Convection with Internal flow Main difference is the constrained boundary layer Inviscid flow region Boundary layer region (r,x) ,6 Hydrodynamic entrance region fully developed region x fd.力 Different entry length for laminar and turbulent flow Compare external and internal flow Externalflow: Reference temperature: Too is constant Internalflow. Reference temperature: Tm will change if heat transfer is occurring Tm increases if heating occurs(Is> Tm) Tm decreases if cooling occurs(Is< Im) Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 7 Convection with Internal Flow • Main difference is the constrained boundary layer • Different entry length for laminar and turbulent flow • Compare external and internal flow: – External flow: Reference temperature: T is constant – Internal flow: Reference temperature: Tm will change if heat transfer is occurring! • Tm increases if heating occurs (Ts > Tm ) • Tm decreases if cooling occurs (Ts < Tm )   ro